Mouthpieces Are for Protection, not Performance

Many athletes are familiar with the use of a mouthguard to protect the teeth, gums, and jaw from damage in contact sports, but fewer people have used them for performance enhancement. However, this trend is on the rise and commercial products are available now for the purpose of enhancing performence. Two recent studies - one with male participants and another with female subjects - were recently published in the Journal of Strength and Conditioning Research to see whether or not this practice is worth our time and money.

The idea of using mouthguards for performance has to do with biting down. This is a principle many powerlifters and other strength athletes use with their grip. Essentially, squeezing hard with the grip causes the force of your grip to radiate out to the rest of your muscles and increases strength. And with grip, it actually works. Many believe this theory would also apply to the jaw muscles. If you clench your teeth, it may be that the strength in the rest of your body is improved.

The science behind the idea, however, has been pretty sparse so far. The first of the recent studies examined the use of a commercially available mouthguard designed specifically for improving performance. The mouthpiece came prepackaged and the participants were coached in proper fitting.

The researchers looked at one rep max bench press strength and jumping power with and without the mouthguard, but gave the participants no instructions to clench their jaws. The idea was that clenching the jaw would come naturally. In this case, with this particular mouthguard, the results were not in favor of mouthguard use. There was no difference in strength or power with or without the mouthguard.

The second study had many differences from the first and was also more detailed. There were three conditions used in this study, and in each of them the participants were instructed to use their jaws in different ways:

Clenching with no mouth piece.

Clenching with a balanced and fitted dental appliance that evenly distributed bite force.

A third group clenched while wearing a fitted appliance that created uneven pressure in the bite. In other words, the bite was only on one side of the mouth.

There were several differences with the second study’s design, including more detail and custom appliances. The second study also focused on the concentric and eccentric performance of isolated knee movement. However, the major difference was in the instruction to bite down.

The researchers learned a little more in the second study, but not much. There was no difference in any of the conditions, with one exception. The eccentric strength in both flexion and extension of the knee was reduced in the group that had the uneven bite. The concentric strength remained the same across all groups.

So it seems that having a mouthguard for strength simply isn’t worth it. Both studies didn’t find much difference between using the performance mouthguard or not, despite the numerous conditions used in the two studies.

But there is something we can take away from the second study. Some people have uneven bites naturally, and this uneven bite might be reducing their eccentric strength, at least if they naturally clench their teeth while lifting. If that’s the case, coaches and athletes may want to have their bites analyzed to check for even distribution. If the bite is uneven, it may be wise in that case to use a mouthguard for the purposes of improving eccentric strength.